What are the guidelines for extubation in a general anesthesia case in the operation theatre?

Extubation Guidelines in the Operating Theatre for General Anaesthesia

All extubations in the operating theatre must be supervised by an anaesthetist, with at-risk extubations performed in the operating theatre environment rather than recovery areas. 1

Pre-Extubation Assessment

Airway Evaluation

• Assess whether bag-mask ventilation would be achievable by evaluating for oedema, bleeding, blood clots, trauma, foreign bodies, and airway distortion using direct or indirect laryngoscopy 1
• Perform a cuff-leak test to assess subglottic calibre: the presence of a large audible leak when the tracheal tube cuff is deflated is reassuring, while absence of a leak around an appropriately sized tube generally precludes safe extubation 1
• Remember that the presence of a tracheal tube may give a falsely optimistic view of the larynx at direct laryngoscopy, and oedema may progress very rapidly 1

Neuromuscular Function

• Ensure complete reversal of neuromuscular blockade using a peripheral nerve stimulator to confirm train-of-four ratio ≥0.9, which reduces postoperative airway complications 1
• An accelerometer is more accurate than visual assessment for train-of-four response 1
• Sugammadex provides more reliable antagonism of rocuronium- and vecuronium-induced blockade than neostigmine 1

Physiological Optimization

• Correct cardiovascular instability and ensure adequate fluid balance 1
• Optimize body temperature, acid-base balance, electrolytes, and coagulation status 1
• Provide adequate analgesia to optimize postoperative respiratory function, while avoiding or cautiously titrating sedative analgesia 1

Equipment and Monitoring Requirements

Essential Equipment

• A difficult airway trolley must be immediately available, along with relevant items such as clip removers and wire cutters 1
• Standard monitoring must be continued including ECG, non-invasive blood pressure, pulse oximetry, and capnography 1
• Capnography should be available and used, as it enables early detection of both partial and complete airway displacement 1

Critical Caveat

• A pulse oximeter is not designed to be a monitor of ventilation and can give incorrect readings in various circumstances; never rely on it as the sole monitor 1

Extubation Technique

Pre-Oxygenation

• Pre-oxygenate with FiO₂ 1.0 to maximize pulmonary oxygen stores, aiming for end-tidal oxygen >0.9 or as close to FiO₂ as possible 1
• Although FiO₂ 1.0 may increase atelectasis, the priority at extubation is maximizing oxygen stores to continue oxygen uptake during apnoea 1

Patient Positioning

• Position the patient head-up (reverse Trendelenburg) or semi-recumbent when possible, as this confers mechanical advantage to respiration and is especially useful in obese patients 1
• For non-fasted patients, consider left-lateral, head-down position 1

Suctioning

• Perform oropharyngeal and bronchial suction under direct vision using a laryngoscope to avoid soft tissue trauma, particularly if there are concerns about secretions, blood, or surgical debris 1
• Laryngoscopy should be performed with the patient in an adequately deep plane of anaesthesia 1
• Do not suction the tracheal tube at the point of extubation, as this can precipitate coughing 1

Extubation Execution

• Ensure minimal interruption in oxygen delivery during the extubation process 1
• Disconnect the circuit and immediately apply supplemental oxygen via facemask 1
• For double-lumen tubes or reactive airways, consider the higher risk of coughing, bronchospasm, and aerosol generation 1

Location and Supervision

Standard Cases

• All extubations must be supervised by an anaesthetist 1
• Routine extubations can occur in the operating theatre or recovery area with appropriate supervision 1

At-Risk Cases

• At-risk extubations must occur in the operating theatre 1
• Patients with airway concerns should either stay in recovery or transfer to a critical care environment 1
• During transfer to recovery or critical care, the patient must be supervised by an anaesthetist 1
• Transfer of at-risk patients from intensive care to the operating theatre for extubation may be appropriate to ensure availability of necessary equipment and expertise 1

Post-Extubation Monitoring

Immediate Observations

• Monitor level of consciousness, respiratory rate, heart rate, blood pressure, peripheral oxygen saturation, temperature, and pain score 1
• Close observation is necessary during recovery, as pulse oximetry alone is insufficient 1
• Capnography using a specially designed facemask aids early detection of airway obstruction 1

Warning Signs Requiring Immediate Action

• Never ignore a patient who is agitated or complains of difficulty breathing, even if objective signs are absent 1
• Early warning signs include stridor, obstructed breathing pattern, agitation, drain losses, airway bleeding, haematoma formation, and airway swelling 1
• Late problems include mediastinitis (severe sore throat, deep cervical pain, chest pain, dysphagia, fever, crepitus) and airway injury 1

Special Considerations for At-Risk Patients

Respiratory Support

• Nurse patients with airway compromise upright and administer high-flow humidified oxygen 1
• Keep the patient starved, as laryngeal competence may be impaired despite full consciousness 1
• Avoid factors that impede venous drainage 1
• Encourage deep breaths and coughing to clear secretions 1
• For patients with OSA, a nasopharyngeal airway may overcome upper airway obstruction, and their home CPAP device should be available 1

Pharmacological Management

• For inflammatory airway oedema from direct airway injury, administer steroids equivalent to 100 mg hydrocortisone every 6 hours, starting as soon as possible and continuing for at least 12 hours 1
• Single-dose steroids given immediately before extubation are ineffective 1
• Steroids have no effect on mechanical oedema secondary to venous obstruction (e.g., neck haematoma) 1
• If upper respiratory obstruction or stridor develops, administer nebulised adrenaline 1 mg to reduce airway oedema 1
• Heliox may be helpful but limits FiO₂ 1

Documentation

• Record clinical details and instructions for recovery and postoperative care on the anaesthetic chart 1
• Document difficulties in the 'Alerts' section of medical notes and in the local difficult intubation database 1
• Record details of airway management and future recommendations 1
• Send a letter to the patient's general practitioner and provide a copy to the patient 1

COVID-19 or High-Risk Infectious Cases

Additional Precautions

• Only essential staff wearing appropriate PPE should be present for extubation 1
• Position the patient upright on a bed or trolley with full reversal of neuromuscular blockade confirmed 1
• Apply a Hudson mask immediately after extubation, then place a surgical facemask over it to cover entrainment vents and reduce contamination risk from coughing 1
• Wait 20 minutes following extubation before transferring the patient from the operating theatre 1